The present invention relates to aerofoils or hydrofoils and, more particuarly, to an aerofoil or hydrofoil having improved lift or thrust characteristics.
Conventionally, aerofoils and hydrofoils are designed to provide maximum lift at a chosen forward velocity or narrow range of velocities, increased lift being provided, when required, by movable flaps, both leading edge flaps and trailing edge flaps.
It has been proposed to utilize the so-called "jet-pump" principle to provide increased lift on an aerofoil or hydrofoil. A jet-pump comprises a high velocity but relatively low mass flow rate primary jet to induce a flow of secondary, ambient fluid in order to enhance the mass flow rate.